Water calorimetry-based beam quality correction factors for carbon and helium ion beams

作者：Lies Verpoest, Séverine Rossomme, Kevin Souris, Thomas Tessonnier, Andrea Mairani, Iván D. Muñoz, Stephan Brons, O. Jaekel, Kilian-Simon Baumann, H. Fuchs, Peter Kuess, Alexandros Douralis, Ana Lourenço, Hugo Palmans, John Aldo Lee · 发表于：Physics in Medicine and Biology · 年份：2026 · DOI：10.1088/1361-6560/ae794e · 研究领域：Radiation Therapy and Dosimetry、Particle accelerators and beam dynamics、Boron Compounds in Chemistry

Abstract Objective. To determine beam quality correction factors, ℏ , in single-layer scanned carbon and helium ion beams using water calorimetry, thereby reducing uncertainties in dosimetry for light ion therapy. Approach. Water calorimetry measurements were performed under harmonized conditions at two synchrotron-based ion beam therapy centers (MedAustron, Austria and HIT, Germany). Measurements were conducted in the plateau region of single-layer scanned beams. Carbon ion beams covered nominal energies from 213.4–402.8 MeV/u, while helium ion beams were measured at 196.3 and 198.8 MeV/u. Multiple cylindrical (IBA FC65-G, PTW 30013) and plane-parallel (IBA PPC05, PPC40; PTW 34001, 34045) ionization chamber types were investigated. Results. ℏ -factors were determined with standard uncertainties of approximately 1%, depending on chamber type and measurement condition. For all investigated chambers, inter-center agreement was observed within the combined standard uncertainties. Chamber-to-chamber variability was below 0.5% for chamber types for which two samples were available, except for the IBA PPC05, for which differences up to 1.3% were observed. For carbon ion beams, the measured ℏ -factors are consistent with previously published water calorimetry-based results. However, systematic deviations up to 3% persist between experimentally determined and Monte Carlo-derived ℏ values. The measured ℏ -factors for helium ions show t...